HAZARDOUS AREAS
Hazardous areas are classified in two distinct groups.
Flammable gases, vapours and liquids make up one group,
which traditionally had been known as Class I. Dusts, fibres
and flyings make up the second group previously known as
Class II. Hazardous areas are classified by zones according
to the length of time the hazard is present or likely to
be present. The table below show the current zones as specified
in the Australian Standards AS/NZS 2430.3.1, AS/NZS
60079.10 and AS/NZS 61241.10
NOTE: Mobile materials handling equipment
is not permitted in Zone 0 or Zone 20
Zones applicable for flammable gases, vapours and liquids
(previously known a Class I)
ZONE
0 |
Flammable atmosphere continuously present
or present for long periods
(more than 1000 hours/year). |
ZONE
1 |
Flammable atmosphere is likely to occur
in normal operations (more than 10 hours/year but less
than 1000 hours/year). |
ZONE
2 |
Flammable atmosphere is unlikely to
occur in normal operations (less than 10 hours/year). |
Zones applicable for dusts, fibres and flyings
(previously known a Class II)
ZONE
20 |
Area in which combustible dust as
a cloud is continuously or frequently present. |
ZONE
21 |
Area not classified Zone 20 in which
combustible dust as a cloud is likely to occur during
normal operation. |
ZONE
22 |
Area not classified Zone 21 in which
combustible dust clouds may occur infrequently and
persist for only a short period. |
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